Heparin-induced thrombocytopenia type II on hemodialysis: switch to danaparoid

We report two pediatric patients with end-stage renal failure who developed heparin-induced thrombocytopenia type II (HIT II) on hemodialysis (HD). Bo th developed acute respiratory distress and chest pain within 30 min of ini tiating the 5th HD session. The platelets dropped during HD from 168 to 38 x 10(9)/l and from 248 to 109 x 10(9)/l, respectively. Marked clots were ob served in the dialyzers. Substitution of heparin with the low molecular wei ght heparin dalteparin had no effect. Switching from anticoagulation to the heparinoid danaparoid resulted in immediate disappearance of all adverse e ffects, and further long-term HD was uneventful. HIT II was diagnosed clini cally; heparin-induced platelet activation test (HIPA) and serum IgG, IgA, and IgM to heparin-platelet factor 4 complexes (HPF4) were both negative. W e conclude that HIT II may occur in children on KD. HIT II is essentially a clinical diagnosis, as HIPA and antibodies to HPF4 are not always positive . Once HIT II is suspected, heparin land low-molecular-weight heparins) sho uld be stopped immediately. Long-term anticoagulation with danaparoid is a valuable option for patients on HD.